Thanks for posting in the Community, CPCBear,
Adding a due date is unavailable in the A/R aging report. Aging reports sort the data in ascending order since it gathers the information from the prior periods.
For the Report period, you can select the options from the drop-down and selecting the As of date. Also, please utilize the Days per aging period and Number of periods to acquire the data you need.
In the meantime, you can run a different report like Transaction List by Date and customise it to include the Due date. You can also save your customised report for future reference.
For reference you can check this link to learn more about: Customise reports in QuickBooks Online.
Feel free to post again in the Community if you have other concerns. I'll be around to help you.
